Water hardness reduction through interactive molecular agitation and filtration

ABSTRACT

The &#34;hardness&#34; of water flowing through a pipe, and attributable to ions dissolved in the water, is reduced by producing molecular agitation in the water to transform the ions into much larger crystals, followed by filtration using a conventional filter having a mesh size much larger than the size of the ions, but smaller than the size of the crystals.

CONTINUING DATA

This application is a continuation-in-part of my U.S. applications, Ser.No. 08/544,156, filed Oct. 17, 1995, issued Mar. 10, 1998 as U.S. Pat.No. 5,725,778; and Ser. No. 08/736,231, filed Oct. 23, 1996, now U.S.Pat. No. 5,846,414.

BACKGROUND OF THE INVENTION

The present invention relates to water purification and moreparticularly to the removal of dissolved minerals and carbonates fromwater in order to diminish its so-called "hardness".

The overwhelming majority of water in the United States is "hard".Elsewhere, this proportion may vary, but hard water is found in many, ifnot most regions of the world. Where it is found, it creates seriousdifficulties. Not only does it cause scale to form inside the pipes,storage vessels, and the like in which the water is contained, but itcauses problems even after passage through these containers. Forexample, hard-water makes it necessary to use excessive quantities ofwater softeners and/or soap or detergent when the water is used forwashing, and it also leaves calcium-type deposits analogous to scale inor on the articles washed with that water. As another example, hardwater dissolves some substances less readily than water whose hardnesshas been reduced, or eliminated.

The substances which cause hardness in water normally are present in theform of dissolved ions, predominantly calcium and bicarbonate ions. Dueto their extremely small size (of the order of 10⁻¹⁰ microns), thesedissolved ions cannot be readily filtered out of the water usingconventional and relatively inexpensive water filters. Rather, moreexotic removal techniques have had to be used, such as reverse osmosisor ion exchanger. Those techniques are too expensive for use in otherthan specialized applications. For example, for domestic usage, themulti-hundred dollar cost of a reverse osmosis installation tends to beregarded as prohibitive by most prospective users, and this problemwould be compounded by the need to professionally service theinstallation, also at substantial recurrent cost for maintenance.

Alternatively, chemicals could be added to the "hard" water to softenit. However, these chemicals, in turn, have residues which have theirown undesirable characteristics. For example, adding sodium chloride(used in conventional water softeners) leaves behind, in the (softened)water, the sodium portion, with its well-known undesirable side effects.

BRIEF DESCRIPTION OF THE INVENTION

Accordingly, it is an object of the invention to provide a waterpurification technique which reduces problems prevailing in the priorart.

It is another object to provide such a technique which reduces thehardness of water without the need for exotic techniques, such asreverse osmosis, or addition of chemicals.

It is still another object to provide such a technique which is asconvenient to utilize as conventional filtration techniques.

These and other objects of the invention which will appear are achievedas follows.

Molecular agitation is produced in the water whose hardness is to bereduced. This is accomplished by means of an induction coil which isapplied to the water-carrying vessel and which is energized by anintermittent unidirectional current, or by an alternating current. Thismolecular agitation transforms the calcium and carbonate ions which arepresent in solution in the water into insoluble calcium carbonatecrystals of many times greater size (of the order of one micron). Thewater containing these crystals is then supplied to a filtration means,which may take any conventional form that is inherently too coarse tointercept the dissolved ions. Such a coarse filtration means may be anordinary fiber filter having a porosity, or mesh size which is typicalof filters for domestic use. Such a fiber filter would have been quiteincapable of filtering out the dissolved ions which impart hardness tothe water in the first place. However, used in interaction withmolecular agitation, fiber filters can readily--andinexpensively--filter out the (relatively large) crystals which arecreated by the molecular agitation, thereby reducing the water hardness.

It should be noted that molecular agitation, by itself, had previouslybeen proposed for a different purpose. Specifically, it had beenrecognized that, particularly when hard water is heated, the dissolvedions such as calcium and bicarbonate in the water form a type of calciumcarbonate which tends to cling to the walls, or adhere to the bottom ofthe vessel carrying the heated water. This creates scale deposits insidethe vessel. By producing molecular agitation upstream from the waterheating, this scale formation process can be reduced, or even reversedso as to remove previously formed scale deposits.

What had not been recognized is that the same kind of molecularagitation can also interact beneficially with inexpensive conventionalfiltration means so as to reduce the hardness of the water.

BRIEF DESCRIPTION OF THE DRAWINGS

For further details, reference is made to the discussion which follows,taken in light of the accompanying drawings, wherein

FIG. 1 is a diagram illustrating the principles of the invention;

FIG. 2 is a diagrammatic representation of an embodiment of theinvention;

FIG. 3 is a diagrammatic representation of an embodiment using adifferent filtration means; and

FIG. 4 is a diagrammatic representation of an embodiment for use in adomestic environment;

FIG. 5 is a diagrammatic representation of a saddle-shaped coil.

It will be understood that these diagrammatic illustrations are notdrawn to scale.

DETAILED DESCRIPTION

Referring now to FIG. 1, this shows a pipe 10, through which flows"hard" water in the direction of arrow 11. This water contains, insolution, calcium ions 12 (represented by small open circles) andbicarbonate ions 13 (represented by small solid circles). A solenoidcoil 14 is wound around a section 15 of the pipe 10. Coil 14 is suppliedwith a square-wave d-c current from a source 16 of such current.

Within section 15, this current causes molecular agitation of the ions12 and 13, which are dissolved in the water flowing through that section15. This state of molecular agitation is diagrammatically represented inFIG. 1 by the pattern of dots 16a. In turn, this molecular agitationcauses controlled precipitation of insoluble calcium carbonate crystals.These crystals are designated by reference numeral 17 in FIG. 1.

Downstream from pipe section 15 there is positioned a filter 18. Asdiscussed more fully below, this filter 18 has a mesh size such that itintercepts the crystals 17. As a result, after passing through filter18, the water flowing in pipe 10 is substantially cleansed of many ofthose dissolved ions 12 and 13, which have been transformed intoinsoluble crystals 17 by the molecular agitation.

Thus, in accordance with the present invention, the filter 18 can have amesh size which is many times greater than the size of the ions 12 and13 which impart the undesired "hardness" to the water. For example,ordinary fabric water filters can be used, such as are readily (andinexpensively) available in hardware and plumbing supply stores. Thesefilters have typical mesh sizes ranging from approximately 1 to 20microns. By themselves, such filters would be totally incapable offiltering out the much, much smaller ions 12 and 13.

In contrast, the large size of the crystals 17 which are produced by themolecular agitation in pipe section 15 does make it possible for such anordinary filter 18 to intercept these crystals 17.

An ancillary benefit of the present invention is this. Thetransformation by molecular agitation of dissolved ions 12 and 13 intoinsoluble crystals 17 also reduces the tendency of these ions to depositon the inside of pipe 10, downstream from pipe section 15, thereby alsoreducing deleterious scale formation in downstream locations. Thisadditional benefit is especially pronounced when these locationsdownstream from section 15 and filter 18 include a place where the wateris heated, e.g. a domestic hot water heater. That is because heatingincreases the tendency toward scale formation, and correspondinglyenhances the desirability of counteracting such scale formation.

Further details concerning the electric current supplied to coil 14, aswell as apparatus suitable for producing such a current, are disclosedin co-pending United States patent application Ser. No. 08/544,156 filedOct. 17, 1995 which issued on Mar. 10, 1998 as U.S. Pat. No. 5,725,778.The contents of that co-pending application are incorporated in thepresent application, as though set forth at length herein.

In practice, the filter 18 of FIG. 1 would preferably not be simply aplug of fabric filtration material, inserted in pipe 10, as shown in theFIG. 1. Rather, there would be used a more conventional filterarrangement, such as diagrammatically illustrated in FIG. 2, to whichreference may now be had.

FIG. 2 shows a pipe 20 through which flows ion-rich "hard" water in thedirection of arrows 21, 22. Molecular agitation is produced inside pipesection 23 by coil 24, which is supplied with square-wave d-c currentfrom source 25. Insoluble crystals are present downstream from section23, due to this molecular agitation. The same comments apply to thisapparatus as to the correspondingly functioning elements of theembodiment of FIG. 1. The difference is that, in FIG. 2, the filter 26is now not simply a fabric filter plug inside the pipe, as was the casein the illustration of FIG. 1, but rather what will be referred to inthis application as a cylindrical filter. This consists of an outercylindrical element 27, having a central, perforated conduit 28 whicheffectively constitutes the filter inlet, and a cylinder 29 of fabricfilter material which surrounds conduit 28 and through which the waterissuing from the perforations in conduit 28 passes on the way back tothe continuation of pipe 20.

This is a well-known type of water filter used, for example, in manydomestic water filtration applications. To service this filter, itsuffices to detach the cylinder 27 from its connections to water pipe20, replace the fabric cylinder 29, and then reattach the assembly tothe water pipe.

The fabric cylinder 29, itself, is available with various mesh sizes,but none which come even close to being able to intercept dissolvedions. In contrast, these fabric cylinders can readily--andinexpensively--be obtained with fine enough mesh size to intercept thelarge crystals formed by the preceding molecular agitation.

Referring now to FIG. 3, this shows apparatus which is similar to thatof FIG. 2, and corresponding elements are therefore designated by thesame reference numerals. However, the filtration means in FIG. 3 doesnot use a fabric filter 29, as in FIG. 2, but a different type ofcylindrical filter.

This cylindrical filter of FIG. 3 also has a cylindrical outer housing30, inside which there is a bag-shaped inner cylinder 31. The waterarriving through pipe 20 is introduced into cylinder 31 at its top. Thiscylinder 31 is made of metal or fabric mesh, with openings which canreadily be made as small as 1 micron. Crystals arriving through pipe 20and in excess of 1 micron size will therefore be intercepted by cylinder31. The water, now freed from these crystals, will pass through the meshopenings in cylinder 31 and into the space between that cylinder andhousing 30. From that space it will flow out of housing 30 and into thecontinuing portion of pipe 20. To service this filter of FIG. 3, itsuffices to detach the housing 30 from its connections to water pipe 20,either replace or clean out the mesh cylinder 31, and then reattach theassembly to the water pipe.

As noted above, a mesh filter such as shown in FIG. 3 can readily have asmaller mesh size than the kind of fabric filter as shown in FIG. 2.However, even those smaller mesh sizes are still much too large tointercept ions, while being capable of intercepting the large crystalsproduced by molecular agitation.

Referring now to FIG. 4, this shows the invention as applied in atypical domestic situation.

The main domestic water pipe 40 has applied to it a solenoid coil 41 forproducing molecular agitation. This coil 41 is diagrammaticallyrepresented In FIG. 4 by the rectangle which bears the reference numeral41.

Pipe 40 then continues to a filter 42 which is diagrammaticallyrepresented by a rectangle bearing the reference numeral 42.

From filter 42, pipe 40 continues to domestic hot water heater 43 andmay also branch to other piping (not shown) for supplying unheated waterfor various domestic uses.

The system of FIG. 4 also includes a d-c current source 44 for coil 41.That current source 44 is a circuit, which can be plugged into anordinary domestic electric outlet (not shown) and which produces asquare d-c output current at a frequency of 500 Hertz and a power levelof 5 watts. Such circuitry may be of entirely conventional constructionand is therefore not further described here. However, for a moredetailed disclosure of such circuitry, reference is again made to theabove-identified co-pending U.S. patent application, Ser. No.08/544,156, filed Oct. 17, 1995, now U.S. Pat. No. 5,725,778.

As for the coil 41, this is preferably of a construction which can bedescribed as "saddle-shaped", and it is positioned eccentrically inrelation to the pipe 40. This type of coil arrangement is disclosed indetail in co-pending U.S. patent application, Ser. No. 08/736,231, filedOct. 23, 1996 now U.S. Pat. No. 5,846,414 whose contents are herebyincorporated in the present application, as though fully set forthherein.

By the use of circuit 44 and coil 41 as disclosed herein, theinstallation of the invention on a domestic water supply becomes asimple matter that even a non-professional should be able to carry out.

All the component parts can be made available for purchase in, forexample, a home improvement store. The circuit 44 would be availablealready pre-connected to coil 41 through the equivalent of an electricalextension cord, and the coil 41 itself would be in one of the formsdisclosed with reference to FIGS. 3, 4 and 5 of the above-identifiedco-pending application, Ser. No. 08/736,231, filed Oct. 23, 1996. Such acoil would need only to be placed around the pipe 40, as shown in saidFIGS. 4 and 5. Domestic water pipes are typically only about 1 to 11/2inches in diameter, so that a correspondingly small coil arrangement 41would suffice. The circuit 44 would then be simply plugged into aconvenient domestic electric outlet and the system would be ready tofunction.

As for filter 42, this would again be any conventional, domestic waterfilter, such as the type illustrated in FIG. 2 of the presentapplication.

In such a domestic application, the interactive effect of molecularagitation and filtration is especially beneficial for the followingreason.

In a domestic hot water heater, such as heater 43 in FIG. 4, the watertends to flow very slowly, or even to stagnate completely when hot wateris not being used. As a result, without the interactive effect of bothcoil 41 and filter 42, not only ions, but even large crystals (howeverproduced) would tend to settle out and deposit on the heated surfacesinside the heater tank, thereby impairing the efficiency of the heater.

By also removing ions and large crystals before they reach the hot waterheater 43, such an efficiency impairment is substantially reduced.

It will be understood that the transformation of ions (12 and 13 inFIG. 1) into large crystals (17) is not necessarily complete. Rather,some ions may escape this transformation, and therefore also escapeinterception by the downstream filtration means (see FIG. 1). However,the hardness of the water will, in any event, be substantially reduced.

Indeed, in laboratory experiments using a system in which the water wascontinuously recirculated through a coil 14 and a filtration means 18,the invention has achieved alkalinity (i.e. hardness) reductions of upto 35%.

It will be understood that many modifications may be made by thoseskilled in the art without departing from the inventive concept.Accordingly, it is desired that this concept be limited only by theappended claims.

I claim:
 1. A system for reducing the "hardness" of water attributableto ions contained in solution in the water, comprising:filtration meanshaving a mesh size substantially greater than the size of said ions;means for transforming at least some of the ions into insoluble crystalscontained in said water and of a size sufficiently large to beintercepted by said filtration means, said means for transformingincludes an induction coil means and means for supplying a time-varyingelectric current, in the form of a square wave d-c current, to said coilmeans, said induction coil means being in a saddle-shaped configurationand positioned in relation to the ion containing water so as to producea time-varying electric and magnetic field within the ion containingwater; and means for supplying said water from said transforming meansto said filtration means.
 2. The system of claim 1, wherein saidfiltration means is a fabric filter.
 3. The system of claim 2, whereinsaid means for supplying said water is a pipe and said fabric filter isof an in-line type used between two pipe sections.
 4. The system ofclaim 2, wherein said filtration means is a cylindrical fabric filter.5. The system of claim 2, wherein said fabric filter has a mesh sizeranging between approximately 1 to 20 microns.
 6. The system of claim 1,wherein said filtration means is a cylindrical metal screen filter. 7.The system of claim 1, wherein the water flows through a pipe and theinduction coil means is positioned to produce said time-varying field inthe water which flows through said pipe.
 8. The system of claim 7,wherein means are provided for heating said water in a locationdownstream from both said coil means and said filtration means.
 9. Thesystem of claim 8, wherein the heating means is a domestic hot waterheater.
 10. The system of claim 7, wherein said coil means comprises atleast one wire coil wrapped at least partially around said pipe.
 11. Thesystem of claim 10, wherein said wrapped wire coil is positionedeccentrically in relation to said pipe.
 12. The system of claim 1wherein said means for supplying water is a pipe and said filtrationmeans is a fabric plug inserted into the pipe.
 13. A system for reducingthe "hardness" of water attributable to ions suspended in the water, thewater being transported by a pipe, the system comprising:an inductioncoil means placed around the pipe in a saddle-shape configuration; meansfor supplying a time-varying electric current, in the form of a squarewave d-c current, to said coil means for producing a time-varyingelectric and magnetic field within the ion containing water andtransforming at least some of the ions into insoluble crystals containedin said water; and filtration means having a mesh size substantiallygreater than the size of said ions for capturing said crystals.